Design Optimisation of Building mounted Wind
Acceleration Aerofoil Wing powering Wind Turbines using
CFD, an integrated Architectural-aerodynamic Approach.
Dr. Abdel Rahman Elbakheit
King Saud University
E-mail: a_rahman41@hotmail.com, Albakheit@ksu.edu.sa
Abstract
This paper represents some work aimed at providing a systematic approach in
building design towards a successful integration of wind harnessing renewable energy
technologies. The approach adopts the use of building forms and profiles to assist local
wind patterns of the site in question to trigger a continuous stream of air that can be
used to power a turbine of a suitable shape and size.
In this sense it takes into consideration the use of building masses and adjacencies to
create such flows, as well as the general outline of the urban settings. This enables the
Architectural design process of form finding and justification in terms of functionality
and economic suitability a further step to achieve sustainability.
In this process computational fluid dynamics CFD provides the corner stone in
evaluating, testing and optimising an envisaged design solution. The capability of the
CFD code to predict the patterns of air movements with magnitude and direction with
potential pressures on surfaces is the most valued privilege.
The study tackled the issue of wind separation in buildings and how to simulate it in
CFD, as well as an investigation into the parameters of wing shapes utilizing wind
separation in buildings to accelerate wind velocities for capturing by wind turbines.
The study concluded that CFD is a good tool for modelling, designing and optimizing
of aerofoil shapes for wind energy utilization. The main parameters affecting the shape
of wing profile for wind harnessing purposes would be: 1- the distance of the wing
from the building surface.
2- The angle of attack of the wing.
This process could magnify natural wind up to 30% increase in low velocities (i.e.,
below 5m/s) and up to 150% in high velocities (i.e., above 5m/s).
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Turbines using CFD, an integrated Architectural-aerodynamic Approach.
1. Wind energy availability
Globally, wind energy has well-established patterns of flow as to the
geographical locations and timing of the year. Although this would be a major
stimulant for any particular location, yet still any site would be unique in terms
of its potential to capture wind energy. This is particularly evident in urban
terrains compared to rural areas. As the presence of building clusters, tall or
short, trees and other obstructions would be detrimental for wind directions
and velocities. However, unlike solar energy wind energy can be available all
the time, if only relevant measures are made to reduce the effect of obstructions
and be assisted with carefully sculpted designs.
The wind prevailing pattern of a particular site can be obtained in the form of
wind-rose diagram as shown in figure 1, from relevant metrological registration
office, showing information about the distribution of wind speeds as well as the
frequency of varying wind directions along the year.
Figure 1: Wind rose diagram shows the wind distribution and likely
frequency plotted as 12 sectors according to the European wind atlas1.
2. Building design Optimisation for potential wind energy collection
2.1. Background
Considerable effort and research have been conducted to establish wind flows
over typical building cross sections through simulation and field-testing. It was
found that at the top corner of a rectangular2 building facing wind direction or
slopped3 roof sides subjected to wind; an acceleration effect of the wind would
take place figure 2.
Figure2 2: Visualisation of the turbulent separation at the leading roof edge of a flat roof.
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The total picture of the flow around a building subjected to wind stream,
(i.e., figure 2) reveals that the flow would be separated at the top of the building
with areas of large pressure in front of the building and for some distance over
it. Areas of re-circulation occur at the top and back of the building as well as in
the foot of the building from the front side.
The flow passing a tall building separates in many ways. Figure 3 shows
separating streamlines in a vertical cross sectional plane in the mean flow
direction being separated in different zones around the building. At the front, the
flow divides upwards and to the sides. The flow around the building separates
at each sharp edge and generates re-circulation.
Figure 3: Flow schematic sketch, with areas of re-circulation in front, top
and back of the building (left to right).
This phenomenon has been studied by many researchers trying to determine
where exactly the limits of these circulations takes place compared to the
geometrical parameters of the building and due to Reynolds stresses. (Schlichting,
H. 19794, Hunt and Smith5 1969, etc6,7,8,9,10,11,12,13,..)
Of all the above-mentioned scenarios of wind separation along the edges of
tall buildings only the acceleration effect at the very front of the building is of
major importance in this study. Therefore buildings, which lie in the wake of
tall buildings, would not take advantage of the acceleration effect due to the
fact that they are under re-circulation flows (turbulence) resulting from other
buildings, Figure 4. Unless they are tall enough to fall outside this effect, then
they can be incorporated with this application within this study. That is simply
because turbulent flow would create problems and lowers the efficiency of wind
harnessing technologies (i.e., wind turbines).
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Figure14 4: Projected areas were re-circulation (turbulences) takes place.
In order to utilise this acceleration to power a building mounted wind turbine,
the flow can be further enhanced through the provision of a wing shape profile
at the start of the corner on the top of a rectangular building or at the top/start
of the ridge of slopping roof.
The main parameters that influence the performance of such a shape would be:
1. The distance the wing is positioned away from the roof. (D) in Figure 5
2. The opening angle of the wing (angle of attack; angle (A) in Figure 5.
Figure 5: Main parameters affecting the performance of a wing shape on top of a building.
The effect of placing such a shape in the accelerated free stream would result
in further increase of flow in the region where it is placed and on the top of
it, hence providing an ideal location to place wind-harnessing technologies.
The wing shape through the above stated parameters of its distance from the
roof and the angle of opening would pose acceleration to air mass flow rate by
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concentrating large amount of air through a restriction. This shape should be of
a suitable material and properly anchored to the building to withstand the likely
high structural loads such as uplifting or drag forces. Figure 6 shows the likely
shape of flow after installing the wing shape on top of the building.
Figure 6: Flow separation after installing a wing shape on top of a building.
Figures 7 and 8 below show a 2D slice of a 3D CFD simulation (i.e., 3D
CFDsimulations3 generally more accurate and reliable in depicting such flows
around buildings).
When comparing figure 7 to figure 2 above we can see that the 3D CFD
simulation provided a fairly close matching flow to that measured or theoretically
established flows shown on figures 3 and 6.
Figure 8, below shows the acceleration effect after placing a wing shape to
figure 7 flow, with the yellow velocity vectors of higher velocity magnitude
(i.e., 25m/s) compared to figure 7, where the velocity was in the region of
17m/s in a free air stream on top of a rectangular building.
2.2. Underline simulation strategies
Since the 1980s, the flow of wind in urban terrain and around buildings
has been intensively studied using CFD. According to Oliveira and Younis
as a consequence of this; the blockage effect imposed by the building on an
approaching wind flow is very important in 2D simulations, requiring a domain
higher than 10H and an upstream developing length longer than 15H (i.e., were
H is the height of the obstacle)
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Figure 7: Velocity vectors depicting flow separation on top of a rectangular building.
Figure 8: Velocity vectors after installing a wing shape on the same building in figure 7.
3.Analysis of wind turbine integration into Architectural Design.
3.1. Optimisation of wing shape position and Angle of attack.
3.2. Introduction
In an attempt to optimise building design for wind renewable energy a design
of a single story detached house is developed figure 9. It has ground and first
floors with a height of 7m on the low side of the pitch to 8m on the high end. The
house was meant to integrate wind turbines and several other renewable energy
technologies, (i.e., Photovoltaic). It is assumed that the site of the house is free
from obstructions to wind flow. In practical terms if there are obstructions it
would be solved by adding more height to the building as shown in figure 4 above.
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3.3. Wind turbine integration
Within urban areas higher grounds or top of buildings would theoretically
be more suited for uninterrupted and more persistent wind flow compared to
lower level areas. In addition to this the flow would be most likely free from
turbulence effects. Due to these reasons, the top of the roof was suggested
as the suitable place where wind turbines will be integrated. The roof shape
of the house is a mono-pitch slopping to one side (i.e., wind direction) with
the lower side on top of a curved curtain wall façade integrating PV modules,
figure 9. This shape would be of little resistance to air flow and is intended to
maximize air mass flow rate at the opposite edge of the roof where the turbines
are placed. A wing like profile is attached to the top end of the roof, and the
turbines are placed underneath it. The approach taken here is to use vertical
axis wind turbines which are compact, produce no noise and are also less risky,
compared to horizontal axis wind turbines which are more subject to failure
of turbine blades and produce much more noise at high wind velocity. Vertical
axis wind turbines when aligned horizontally as in figure 9 and figure 10 can
also be installed on top of the terraced or detached houses.
Figure 9: Typical wind turbine integrated in a prototype-detached house,
Wing profile on high end of the roof.
Figure 10: Typical wind turbine integrated in a prototype-detached house,
Wing profile on low end of the roof.
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Turbines using CFD, an integrated Architectural-aerodynamic Approach.
3.3.1. Design optimisation for the height of the turbine slot 15
In order to investigate the effect of varying the proximity of the wing profile
in relation to the roof and finding the optimum height that produce maximum
wind speed for turbine operation. A number of wing proximities to the roof are
studied. These range from 25cm to105cm.
The study15 is carried out using computational fluid dynamics CFD. A 2-D
unstructured grid was chosen to simulate the wing on top of the house, with
the above-mentioned range of distances from the rooftop, while keeping the
building dimensions intact.
3.3.2. Effect of Domain size
As the main point of this investigation is to determine the potentially optimum
distance from the roof top where the wing profile can be located, it is essential
to employ a domain which can provide a plausible description to the flow of air
in response to the change of the wing distance from the roof surface, Figure 11.
Figure 11: 2D mesh for the case of 85cm distance between wing and rooftop.
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Figure 12: Resulting velocity vectors for the case of 85cm distance between wing and rooftop. (Large grid
under Reynolds model of Turbulence).
Figure 13: Resulting velocity vectors for the case of 85cm distance between wing and rooftop. (Large grid
under K-ε of Turbulence).
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Design Optimisation of Building mounted Wind Acceleration Aerofoil Wing powering Wind
Turbines using CFD, an integrated Architectural-aerodynamic Approach.
3.3.3. The effect of different models of turbulence
The flow around the building and its wing is totally turbulent as the Reynolds
number for this problem is 6x106 based on the characteristic length D, taken as
the length of the wing (i.e., 6m long).
A comparison of the flow obtained by Reynolds stresses and the industry
standard k-ε models is made for the grid, figures 12 and 13. The later model (i.e.,
k-ε), under estimate the area of recirculation at the lower part of the roof, while the
former model, projects the recirculation in areas where the later model couldn’t.
This result also provide evidence that the configuration of the building and
roof form accelerate air at the eave and after it, much more than the anticipated
position between the wing and the roof top. Therefore it might be better to
relocate the wing profile on the lower part of the roof to boost the acceleration
effect further in the region below the wing.
The convergence rate for these models are for k-ε model will converge at
around 400 iterations and more, While Reynolds Stress model can converge up
to 750 or more.
3.3.4. The effect of wing positions on top of building roof
This particular point is a result of examining the nature of the flow resulting
from choosing the design configuration in question, presented by the prescribed
model of turbulence (i.e., Reynolds Stress as explained in point 3.3.3 above).
The flow seems to separate better at the eave and the acceleration effect is
experienced there and beyond. So at this point, we can quantify how good is it
to shift the wing from the back of the roof to the front figures 9 to 10 above. To
do this, the same wing has been located at a distance of 85cm from the roof in
two scenarios, one at the front and the other at the rear of the roof. The results
obtained for the rear wing is shown in figure 12 above while the results of front
wing are presented in figure 14 below. The two cases were identical in every
aspect, as well as both of them are run under Reynolds stress model. So the only
difference is the shift in the wing position from the top edge of the roof to the
lower edge of it. The two cases were run under an assumed inlet speed of 10m/s
from the left hand side of the domain.
The front wing position was (i.e., figure 14) the highest resulting velocities
under the wing. i.e., 23.53 m/s. while the rear wing position gave a maximum
speed of 4.75m/s only. That is almost ¼- times of that of the front position.
Also an important point here is that the flow has mainly accelerated under
the wing in the whole domain as shown in figure 14. Whilst in figure 12 the
flow did affected the domain more than it did for the under wing area.
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3.3.5 The effect of coplanar wind Directions
A comparison is made between the cases where coplanar wind directions can
be expected. For a 2-D case this normally means two lateral directions opposing
each other. (i.e., windward becomes leeward and vice versa). In actual terms this
can be learned from a wind rose diagram, therefore it would be anticipated that
the main direction would be the one studied with the direction opposite as just a
check to see how the design perform in a different scenario, which is normally
the second best. Sometimes according to the site characteristics it may have a
wind pattern of high velocity from a particular direction at a certain time of the
year and its reverse (i.e., 180º) on a different one. So in this particular situation
a 2-D simulation for the design shape would be a great advantage.
Figure 14: Velocity vectors for the wing shape positioned above the eave in the front of the house.
Here we can take the grid cases where the wing is placed at either the lower
side or the upper side of the roof. Discussed earlier at 3.3.4, and having the wind
subjected from the left side of the domain as the front wind and the opposite
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Turbines using CFD, an integrated Architectural-aerodynamic Approach.
side as the back wind. Again the resulting velocity underneath the wing will be
the major factor to determine the most suitable design configuration.
Table 1: Effect of the wind direction at the front edge of the building.
Direction of the wind
Resulting velocity below the wing.
Front wind
Back wind
23.53
3.5
Table 2: Effect of the wind direction at the rear edge of the building.
Direction of the wind
Resulting velocity below the wing.
Front wind
Back wind
4.75
14.3
From tables1 and 2 above, it is clear that the scenario where the wind coming
from the front side and the wing on the lower position would generate the most
of acceleration (i.e., 23.53m/s) within the studied scenarios. While the scenario
where the wind coming from the back side would be more favourable for the
upper wing position producing 14.3m/s.
However, based on the flow patterns generated by the two different positions
of the wings, it seems that the lower position is more favourable. But the upper
position can be better performing if the wind came from the back side. In this
situation the choice of the location of the wing would be based on the average
percentage of yearly wind direction coming from the most frequent wind side,
as depicted by the wind rose diagram.
4. Summary of optimising the wing proximity to the roof of the house
This point summarizes the resulting optimisation for the proximity of the wing
to the roof, the wing is located at a lower position on the roof as explained in point
3.3.5 above. Figure 15 below, sums the resulting velocities from the different
proximities of the wing after applying a range of 10 consecutive velocities
through the inlet of the domain. The resulting velocities tend to increase with
the increase of the distance from the roof up to width of 85cm, and reduce
after that. Maximum velocities resulting are within a region of 25m/s.When
plotting the velocity profile along the different wing proximities to the roof as
seen in figure 16, below. We find that most of the plotted resulting velocities do
increase with the increase of gap distance from the roof, but up to a distance of
85cm and decreases gradually after that. Therefore the distance of 85cm would
be the optimum proximity of the wing to generate maximum wind speeds.
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Figure 15: Summary of different proximities of the wing to the roof and its effect of velocity. generated.
Figure 16: Comparison of the resulting velocities due to examined widths at various tested velocities.
5. Summary of optimisation of wing front shape
The second parameter which determines the magnitude of wind speed at the
locality of wind turbine is the wind profile (i.e., geometry). The wing shape
need to be designed to maximise the wind speed, by allowing as much wind
to be captured and also reduce pressure drop as well as turbulence flow. After
establishing the optimum distance the wing need to be placed away from the
roof, a further enhancement to the wing shape to enable it to capture more wind
would be theoretically possible. This could be by increasing the opening angle
of the wing figure 17 below.
However, it is fairly safer to use more monolithic construction materials
(i.e., concrete, etc), which are less susceptible to high uplift forces. But that
obviously necessitate a proper structural anchoring of the wing. Figure 17
shows the suggested increase in the opening angle by an increment of 2º from
the base angle 20 on wards to 30º and 50º.
By this way the wing takes a shape of an aerofoil that enhances the air flow.
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Turbines using CFD, an integrated Architectural-aerodynamic Approach.
By increasing the front attack angle of the wing, more wind is captured by the
wing, this increases the mass flow rate through the space beneath the wing. It
is assumed that optimum front attack angle would be reached where the mass
flow rate is at maximum and the aerofoil shape of the wing is optimised.
5.1. Effect of increasing the angle of attack
As proposed in point 3.1 and 6 above that more opening for the angle of
attack would produce more capturing of wind (i.e., air mass flow rate) and
therefore more energy. This point however introduces the effect of a large grid
depicting a wider and more precise vision of the flow around the building and
the wing. By doing so, more realistic results and therefore conclusions can be
arrived at. Nevertheless, with the large grid the use of Reynolds stress module
of turbulence would slow down the convergence considerably. Hence, the
use of the module (k-ε) would be recommended without appreciable loss of
accuracy in predicting the flow patterns. Figure 18 below, depicts the effect
of investigating the opening angle of the wing by using large grid cases under
(k-ε) model. The figure shows the resulting velocities obtained after applying
10-consecutive air velocities through the inlet starting from 1m/s upwards. The
profile of the graphs for all angles predicts an increase in the resulting velocities
with the increase of angle of the front of the wing from 30º up to 50º. However,
the result of angle 60º was below that of 50º. This suggests that angle 50º would
be the optimum choice for this wing. Figure 19 below shows that all the tested
velocity range (i.e., from 1-10m/s) there is a peak value of resulting velocity at
angle 50º. This confirms the fact that this is the optimum angle for this wing.
Figure 17: A schematic showing the different opening angles of wind energy capturing wings.
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Figure 18: Variation of resulting wind velocities with wing angles at
different input wind speed, In Large grid cases.
Figure 19: Comparison of the resulting velocities due to examined widths at various tested velocities and
angles of attack, in large grid cases.
However, these figures (i.e., 18 and 19) also reveal that angle 20 º, which
is the initial angle of the wing front, has the highest resulting velocity in all
the range of tested velocities. Therefore, all the resulting velocities from the
other angles expect those of angle 50º would be lower than it. This suggests
that the large grid has exposed the real flow more clearly and that there would
be a possibility for wind to be deflected away from the turbine areas with the
increase of angle of attack, but not at 50º. The predicted resulting flow vectors
around the wing after applying the angle of attack of 20-60º are shown in figures
20 to 24 below.
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Turbines using CFD, an integrated Architectural-aerodynamic Approach.
Figure 20: Velocity vectors for wing front angle of attack 20º, in a large grid case.
Figure 21: Velocity vectors for wing front angle of attack 30º, in a large grid case.
Figure 22: Velocity vectors for wing front angle of attack 40º, in a large grid case.
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Figure 23: Velocity vectors for wing front angle of attack 50º, in a large grid case.
Figure 24: Velocity vectors for wing front angle of attack 60º, in a large grid case.
These figures (i.e., 20-24) show that the air would have a stagnant point
appearing just after the wing tip point (i.e., the dark blue point on left side of the
wing). From wing of angle 30º onwards. This point tends to move closer into the
gap between the wing and the roof as the angle of attack increases. The increase
of the of the angle of attack lead also to a larger wind separation from the tip of
the wing upwards and at the back of the wing, causing wind to deflect upwards
instead of the area between the wing and the roof. Therefore reducing wind
speed resulting, this confirms the fact that the large domain would be essential
to investigate the angle of attack of the wing. Despite the fact that there is an
increase of velocity with the increase of the angle of attack, the nature of flow
made this increase falls behind what was in the initial case of angle 20º. Hence
the wing angle of attack can affect the speed generated by the wing according
to the shape it is in, either positively or negatively.
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Turbines using CFD, an integrated Architectural-aerodynamic Approach.
6. Power estimation
The power in the wind can be expressed as:
Ρw = 0.5 ρAν 3 ......................................................................... (1)
Where, Pw = power in the wind (W), ρ = air density (kg/m3), ν = wind
velocity (m/s), A =swept area of rotor (m2). The power in the wind increases
with the cube of the wind speed, which explains why wind turbines tend to be
located at relatively windy sites and trend towards increased tower height to
raise the turbine higher avoiding turbulence flow.
6.1 Effect of wing front angle and wing Proximity on the power output
The power output from a wind turbine located under the wing depends
basically on the resulting wind velocities. The power output is given for a unit
area (W/m2), and the resulting power at each speed and wing angle examined
are obtained as presented on figures 25 and 26, which show the general trend of
the power generation with the increase of wing angle. With the increase of angle
of attack from 20-50º there is a resulting increase of wind speed and therefore
the power production. However increasing the angle to 60º would reduce the
resulting power; therefore the angle of 50º would be the optimum angle for this
system. Yet there is a large unsteadiness predicted on the percentage of increase
of power at all angles figure 26.
Figure 25: Resulting power output at different wind velocities and angles of wing.
Figure 26: Percentage of power increment as the angle of wing increases.
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7. Conclusions:
- Computational fluid dynamics CFD can provide detailed descriptions
and guidance on the physical designing and placing of wind harnessing
technologies within the built environment.
- An increase in the upstream wind velocity in the region of 30%- 150% is
theoretically possible with building design and wind catching shapes and
forms considered in this analysis.
- The analysis has proved that introducing aerofoil shapes such as wings
suitable at the top and corners of buildings have the potential to provide
wind velocity boosting, which can be harnessed using suitable wind
turbines.
- The use of aerofoil shapes into buildings can be either during the initial
design stages or retrofitted to existing buildings. In either case they can be
more cost effective for small (i.e., less than 10kw) integration compared to
large-scale machines (i.e., >100kw). That is due to the reduction of capital
cost, maintenance cost and there are more prospects of wind capturing
within small sites and high-rise buildings.
- The possibility of better operational management, as in the case with multismall scale systems compared to single large machines (i.e. possibility of
small scale turbines backup each other to produce the required output.
- The process of designing aerofoil shapes necessitates some feedback
assessing the structural loading and implications as to the effect of induced
pressure and drag forces on buildings.
- The main parameters affecting the shape of a wing profile for wind
harnessing purposes would be: 1. The distance of the wing from the
building surface.
2. The angle of attack of the wing.
- The study shows that the angle of attack of 50º would provide the optimum
wind speed for the design of wing shape under question.
- For the studied wing shape, the optimum proximity of the wing to the roof
surface was found to be 85cm. This distance provided the best resulting
velocities for the air passing in between the wing and the roof surface.
- The study showed also that the position of the wing on the top of the roof
of the house either in the front or rear can affect the resulting performance
of the wing according to the direction of the incident wind.
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Turbines using CFD, an integrated Architectural-aerodynamic Approach.
References
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buildings, Journael of wind engineering and industrial Aerodynamics 86 (2000) 203220.
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Journal of Wind Engineering and Industrial Aerodynamics, Volume 86, Issues 2-3, June
2000, Pages 203-220 Paulo J. Oliveira, Bassam A. Younis
10 Hunt, J. C. R., “Wakes behind Buildings, I 1 A paper presented to The Atmospheric
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11 Counihan, J., Hunt, J. C. R., and Jackson, P. S., “Wakes behind Two-Dimensional Surface
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14 AWEA slide Show, www.awea.org/pubs/documents/swslides/toc.htm, June 2006.
15 Elbakheit A.R. ‘Enhanced Architectural Integration of Photovoltaics and Wind Turbines
into Building Design’. PhD Thesis 2003-2007, Nottingham University, UK.
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‫طريقة مثلى لت�صميم املباين املتالئمة مع توربينات ت�سريع الرياح با�ستخدام‬
‫برنامج (‪ :)CFD‬منهجية لتكامل العمارة وطاقة الرياح امل�ستدامة‬
‫د‪ .‬عبد الرحمن البخيت‬
‫كلية العمارة والتخطيط‬
‫جامعة امللك �سعود‬
‫الربيد االلكرتوين‪a_rahman41@hotmail.com, Albakheit@ksu.edu.sa :‬‬
‫ملخ�ص‪:‬‬
‫تهدف هذه الورقة لإيجاد طريقة مم ّنهجة للت�صاميم املعمارية من �أجل اال�ستخدام الأمثل لتكنولوجيا و طاقة الرياح يف املباين‪ .‬تتبنى‬
‫الطريق ��ة املتبع ��ة ا�ستخدام الرياح ال�سائ ��دة يف املوقع املعنى وكتل وهيئات املب ��اين بالإ�ضافة �إىل �أ�شكال من الأجنح ��ة الهوائية لت�سريع‬
‫الري ��اح لكي يت�سنى ا�ستخدامها لت�شغيل مراوح التولي ��د الكهربائي ذات الأ�شكال والأحجام املنا�سبة ‪ .‬بهذا االجتاه ف�إنها تتعامل مع كتل‬
‫املب ��اين و عالقاتها م ��ع حميطها لتفعيل التيارات الهوائية و لذلك ف�إنها تعطى للت�صميم املعم ��اري يف حماوالت اختيار و �إيجاد هيئات و‬
‫�أ�شكال املباين و جدلية منا�سبتها لوظيفتها املطلوبة و اجلدوى االقت�صادية للت�صميم (ومن ثم امل�شروع ) بعدا �آخر لتحقيق اال�ستدامة‪.‬‬
‫(حو�سبة حركة املوائع ) حجر الزاوية يف اختيار ‪ CFD‬يف هذه الطريقة املتبعة ‪ ,‬ي�أخذ برنامج احلا�سوب امل�سمى‬
‫وتقييم و حت�سني الأداء للت�صميم املعماري حتت الدرا�سة‪ .‬مقدرة هذا الربنامج يف ر�صد و توقع حركة الهواء و اجتاهها �سرعة و �ضغطا‬
‫‪...‬الخ هي امليزة الكربى للربنامج‪.‬‬
‫تطرقت الدرا�سة لظاهرة انف�صال كتل الهواء نتيجة العرتا�ضها بوا�سطة كتل املباين و ما ينتج عنه من ت�سريع للهواء مما يجعله �صاحلا‬
‫لال�ستخدام يف توليد الطاقة الكهربائية بوا�سطة املراوح التوربينية و�أ�شكال من الأجنحة املنا�سب و�إمكانية حماكاتها بالربنامج املذكور ‪.‬‬
‫تخل� ��ص الدرا�س ��ة ب ��ان الربنامج املذكور مبثاب ��ة �أداة فعالة لت�صميم و تقييم �أ�ش ��كال الأجنحة ال�ستخدامها يف توظي ��ف طاقة الرياح يف‬
‫املباين‪ .‬كما تخل�ص �إىل �إن خوا�ص هذه الأجنحة ممثلة يف‪:‬‬
‫‪ .1‬زاوية مواجهتها للرياح‪.‬‬
‫‪ . 2‬بعد هذه الأجنحة من �سطوح املباين‪.‬‬
‫هي �أهم العوامل امل�ؤثرة على �سرعة الرياح الناجتة من ت�صميم الأجنحة‪.‬‬
‫به ��ذه الطريق ��ة ميكن زي ��ادة �سرعة الرياح بواقع ‪ %30‬للرياح الطبيعي ��ة املنخف�ضة ال�سرع ��ة (‪ 5-1‬م‪/‬ث) واىل ‪ %150‬للرياح الطبيعية‬
‫املرتفعة ال�سرعة (من ‪5‬م‪/‬ث ف�أكرث )‪.‬‬
‫‪King saud university - College of Architecture and Planning‬‬
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